Intervention (I): botulinum toxin

Journal of Dentistry and Oral Epidemiology

Introduction

Temporomandibular disorders (TMD) have been attributed a group of clinicalconditions involving thetemporomandibular joint (TMJ), masticatory muscles and associated structures [1]. In the adult non-patient population, TMD have been affected approximately 33 % at least one symptom TMD sign in 40 % - 75 % of the population [1]. TMD most common symptom is pain in the temporomandibular joint (TMJ), in the periauricular area or masticatory muscles, TMJ sounds, and by deviations or restricted jaw opening capacity [2]. TMD diagnosis on the determination of pathology using an anatomic and functional etiology, is divided into arthrogenic or myofascial TMD, respectively [3, 4]. Generally, myofascial disorders are the most common TMD complaint of patients seeking treatment [5]. Myofascial pain is related with the pain from hyperfunctioning masticatory muscles leading to chronic myositis [3]. The myofascial pain syndrome (MPS) is increasingly present in the routine ofpeopledue toincreased stress, environmental conditions and hormonal factors [6]. The individual may present chronic or acute pain in the region of the chewing muscles, usually with the formation of trigger points that may be active or inactive. The individual suffering from MPS can experience from functional difficulties such as chewing and talking to social restrictions due to the pain process, bringing psychosocial damage from depression [6]. The myofascial pain rate is 50 % to 75 % of the population at some point in their lives and another 20 % to 25 % of % population suffer symptoms but do not seek treatment [7]. This represents a major social and public health impact worldwide. According to the American Academy of Orofacial Pain and other worldwide consensus, treatment should always begin in the most conservative forms, such as the use of myorelaxant plaques and counseling, evolving step by step according to the individual responsiveness of the patient and intensity of the pain. The use of medications such as anti-inflammatory, muscle relaxants, antidepressants and anticonvulsants should also be considered [2, 8-11]. Botulinum toxins are produced by a gram-positive anaerobic bacterium called Clostridium botulinum. The Botulinum acetylcholine from the nerve endings producing dose-related weakness or paralysis of the skeletal muscles [12]. Regarding TMD, TBX-A is routinely used in recent years as primary or complementary treatment for MPS [3, 13]. In addition, it is also used for treating bruxism, disorders associated with TMJ disk displacement and habitual mandibular dislocation [12]. In special, on MPS treatment the BTX-A has been demonstrated advantages as pain relief [14]. TxB-A presents anti-inflammatory and analgesic action, because besides inhibiting the release of acetylcholine, TxB-A would have an inhibitory action on other neurotransmitters and neuropeptides, such as glutamate, CGRP and substance P responsible for the neurotransmission and/or peripheral and central sensitization of the pain pathway [15, 16]. Although the use of botulinum toxin has become popular, there is little evidence of its effectiveness in reducing myofascial pain and improving function over time. Thus, this systematic review compared the use of botulinum toxin to other treatments reduce the intensity of myofascial pain in adult patients.

Material and Methods

This study was registered on International Prospective Register of Systematic Reviews (PROSPERO) database under the number CRD42020141166 and follow the

PRISMA recommendations [17, 18]. It was performed from August 2019 to March 2020, at on University Positivo (UP), Curitiba, Paraná, Brazil. The search strategy was developed the basis of the concepts of population, intervention, and comparison (PICOS) Within each concept, we combined the controlled (Medical Subject Headings terms) and free keywords with the Boolean operators OR and AND. The PICOS acronym was: 1. Population (P): adult patients with myofascial pain 2. Intervention (I): botulinum toxin 3. Comparison (C): other treatments (saline solution, laser therapy and occlusal splints). 4. Outcome (O): decreased the intensity of myofascial pain 5. Study type (S): randomized clinical trials To identify trials to be included for this review, we searched on the electronic databases MEDLINE via PubMeb, Scopus, Web of Science, Latin American and Caribbean Health Sciences Literature database (LILACS), Brazilian Library in